The long-term objective of this project is the improvement of procedures for quantitative analyses of clinical and biological samples by development of a new generation of mass spectrometers whose performance surpasses that of available models. An ongoing phase of this endeavor (GM20850) is developing and testing a new electro-optical ion detector (EOID). Placed at the focal plane of a Mattauch-Herzog mass spectrometer, this sensor possesses electron multiplier sensitivity for simultaneous ion detection in a 36:1 mass range. In the three-year project proposed herein, the development of the EOID for mass spectrometers will be continued with the following specific aims: 1. modify the current instrument and new devices to reduce complexity and increase reliability; 2. develop a readout system, probably a diode array device, better than the current vidicon camera; 3. determine the ultimate sensitivity of EOID devices (which should be 10-100 ions with vidicon cameras and single ion with a diode device); 4. demonstrate highest attainable mass resolution with an EOID by constructing a limited segment device from the smallest available resolution elements; 5. assemble a data acquisition system for efficient testing, housekeeping, calibration and initiation of biomedical research activities; 6. produce detailed documentation of an EOID device to facilitate replication by others of this new technology; 7. define and partially implement automation for the EOID mass spectrometer system; 8. develop pyrolysis mass spectrometry using an EOID device as a method for classification of solid specimens; 9. exploit extreme sensitivity of EOID in demonstration studies with biomedical collaborators in peptides research and assays of prostaglandins, amino acids, organic acids, steroids, and drugs in biological specimens.